Dissipative superfluids, from cold atoms to quark matter

Instituto de Ciencias del Espacio (IEEC/CSIC) Campus Universitat Aut`onoma deBarcelona, Facultat de Ci`encies, Torre C5 E-08193 Bellaterra (Barcelona), SpainSome results about dissipative processes in superfluids are presented.We focus on fermionic superfluidity and restrict our analysis to the contri-bution of phonons to bulk viscosity, shear viscosity and thermal conduc-tivity. At sufficiently low temperatures phonons give the dominant contri-bution to the transport coefficients if all the other low energy excitation ofthe system are gapped. We first consider a system of cold fermionic atomsclose to the unitarity limit. Then we turn to the superfluid phase of quarkmatter that may be realized at high baryonic density.PACS numbers: 47.37.+q,97.60.Jd,21.65.Qr